The open-end wrench used for the outer hexagon corresponds more accurately to the hexagonal nut, as there are hexagonal head bolts and small hexagonal head bolts.
Common open end wrench specifications – corresponding thread specifications
7-M4
8-M5
10-M6
14-M8
17-M10
19– M12
22– M14
24-M16
27– M18
30-M20
32– M22
36-M24
41-M27
46-M30
55-M36
65– M42
The minimum specification of the complete set of hex wrenches is 3, corresponding to S3=M4, S4=M5, S5=M6, S6=M8, S8=M10, S10=M12, S12=M14-M16, S14=M18-M20, S17=M22-M24, S19=M27-M30, S24=M36, S27-M42. Calculation method for the diameter of the threaded bottom hole before tapping; For brittle materials, the basic size is -1.0826 pitch, while for plastic materials, the basic thread size – pitch+0.1
Brittle materials are in a pure cutting state during tapping, and the bottom hole size is the diameter of the thread base circle. Plastic materials undergo plastic deformation due to the material being subjected to force during tapping, and the material will move towards the smaller diameter of the thread. Therefore, the bottom hole should be appropriately enlarged. For threaded holes below M6, regardless of material properties, follow the basic size pitch uniformly
Wrenches are classified according to their purpose, style, etc. A solid wrench: a fixed size opening is made at one or both ends to twist a certain size of the nut or bolt. Box wrench: With working ends with hexagonal or hexagonal holes at both ends, suitable for situations where the working space is narrow and ordinary wrenches cannot be used.
Dual purpose wrench: One end is the same as a single end solid wrench, and the other end is the same as a ring wrench. Tighten bolts or nuts of the same specifications at both ends.
Monkey wrench: The width of the opening can be adjusted within a certain size range, and it can rotate bolts or nuts of different specifications. Hook wrench: also known as crescent wrench, used to turn flat nuts with limited thickness. Socket wrench: It is composed of multiple sockets with hexagonal or hexagonal holes and equipped with various accessories such as handles and extension rods. It is particularly suitable for turning bolts or nuts with very narrow positions or deep depressions. Internal hexagonal wrench: an L-shaped hexagonal rod wrench designed specifically for turning internal hexagonal screws. Torque wrench: It can display the applied torque when tightening bolts or nuts, or when the applied torque reaches the specified value, it will emit a light or sound signal. A torque wrench is suitable for assembly work with clear specifications for torque magnitude.
